In the second half of the 19th and 20th centuries, the liberal paradigm – with its emphasis on growth, peace and the mutual benefits of trade – was the dominant force in international economic relations. In the 21st century, in contrast, we appear to be witnessing the birth of a new age of economic nationalism. This issue of Global Challenges surveys the new economic order and examines the range of challenges it brings: from increasingly mercantilist trade policies and the growing use of sanctions as a policy tool to a "neocolonial" scramble for natural resources.